Apparently there is nothing wrong with the control response or the interpretation of motions. There's a more in-depth and informative review here.
It seems that unlike the likes of Red Steel 2 and Tiger Woods the game doesn't hold your hand and isn't forgiving. When throwing punches you need to make sure that you're standing the right distance away from your opponent otherwise if you're standing too close it may appear that your punches are not responding to your actions. From the iWaggle review I get the impression that this takes a great deal of skill to play well and has a steep learning curve...which makes a change from just about every game released these days being too easy. On the strength of the IWaggle review I'm going to buy this game.
It'll get similar reviews to the likes of the Video Gamer and IGN one unfortunately, but not because the game or the controls are crap, but because it's a true fight simulator and for most reviewers (who will have completely missed the observations made by some guy that isn't actually paid to do reviews) the game will be too difficult. I'm relishing playing a game that requires a great deal of time and effort to master for once. A definite purchase from me, check out the iWaggle review before you make your decision.
